Patents Assigned to Sauer-Danfoss (Norborg) A/S
  • Hydromechanical transmission with differential steer
    Patent number: 6932733
    Abstract: A transmission has an HMT which is in parallel with an HST both driving two planetaries which are used for forward/reverse and for differential steer. A two or three mode HMT is created by having a first HST in parallel with two or three mechanical power paths defined by separate clutches. One clutch has a speed reversing gear to produce reverse output speed. A four-element planetary sums the parallel flow and delivers variable speed and torque to two output shafts. The differential steer is created by two planetaries connected with the outputs of the HMT and a second HST. The planetaries have a speed reversing gear on one power path connection. The second HST controls the differential speed between the output shafts by adding speed to one and subtracting speed from the other.
    Type: Grant
    Filed: November 22, 2002
    Date of Patent: August 23, 2005
    Assignee: Sauer-Danfoss Inc.
    Inventor: Frederic W. Pollman
  • Flow sharing priority circuit for open circuit systems with several actuators per pump
    Patent number: 6931847
    Abstract: A priority circuit is provided that is in communication with an open circuit pump and priority and auxiliary systems. The circuit comprises a first valve with an inlet in communication with the pump, an outlet in communication the priority system, and a load sensing inlet in communication with the priority system, wherein the first valve modulates to maintain a predetermined pressure differential between pressure at the load sensing inlet and pressure at the outlet. The circuit further comprises a second valve with an inlet in communication with the pump, an outlet in communication with the auxiliary system, and a load sensing inlet in communication with the priority system, wherein the second valve is normally closed and opens when pressure at the load sensing inlet of the second valve is less than pressure at the inlet of the second valve minus the predetermined pressure differential of the first valve.
    Type: Grant
    Filed: March 4, 2004
    Date of Patent: August 23, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventors: Charles D. Throckmorton, Michael D. Gandrud, Jimmy W. Bolinger
  • Hydraulic machine
    Publication number: 20050180873
    Abstract: The invention concerns a hydraulic machine with a set of teeth, having a toothed ring with an inner toothing and a gear wheel with an outer toothing, the gear wheel rotating and orbiting in the toothed ring, the inner toothing and the outer toothing touching each other in contact areas, thus separating pressure chambers, and with a valve arrangement controlling a connection between a connection arrangement having a high pressure connection and a low pressure connection, and the pressure chambers. It is endeavoured to achieve a stable operation, particularly with low speeds. For this purpose, each contact area is provided with an opening, which, at the time when a pressure chamber reaches an extreme value of its volume, produces a short-circuiting with the neighbouring pressure chamber.
    Type: Application
    Filed: February 27, 2003
    Publication date: August 18, 2005
    Applicant: Sauer-Danfoss Aps
    Inventors: Kim Hansen, Claus Johansen, Rene Andersen
  • Charge/auxiliary circuit for reducing power losses in hydrostatic systems
    Publication number: 20050178117
    Abstract: A charge pump is provided with two independent outlets that can satisfy the pressure requirements of both a charge circuit and an auxiliary circuit. Preferably, the charge pump is a multiple roller vane pump that has at least one inlet and two outlets independent of each other. The first outlet is in fluid communication with a charge circuit, and the second outlet is in fluid communication with an auxiliary circuit. Because the two outlets are independent of each other, the roller vane pump is able to satisfy the pressure requirements of both the charge and auxiliary circuits. Preferably, the two outlets are diametrically opposed to each other, thereby reducing the load on the driveshaft. Additionally, the roller vane pump may include a second inlet independent of the first.
    Type: Application
    Filed: February 18, 2004
    Publication date: August 18, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventors: Michael Betz, Jeff Herrin, Alan Johnson
  • Axial piston machine having a pilot control device for damping flow pulsations and manufacturing method
    Publication number: 20050180872
    Abstract: The invention relates to an axial piston machine having expellers arranged in a rotating cylinder block, and a valve plate which connects the expellers via valve openings to a port, and having a pilot control device for reducing volume flow pulsations. The pilot control device comprises at least one inertia duct which has a cross-sectional area of less than 3 rum2 and extends along the valve plate in its circumferential direction over at least 45°. The valve opening is effectively connected to the expeller which opens into it by this inertia duct during a specific time period before, in the course of the rotation of the cylinder block, the expeller is connected to the port. In the process, the pressures prevailing in the expeller space and in the port are equalized under the control of the inertia of the oil column which is located in the inertia duct.
    Type: Application
    Filed: January 14, 2005
    Publication date: August 18, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventor: Hans Esders
  • Electro-hydraulic power unit with a rotary cam hydraulic power unit
    Publication number: 20050175479
    Abstract: An electro-hydraulic power unit is disclosed that includes a housing filled with hydraulic fluid. A hydraulic power unit is disposed within the housing, the power unit having a mechanical power shaft. Additionally, an electric machine is disposed within the housing adjacent to the hydraulic power unit, the electric machine having a rotor secured to the mechanical power shaft of the hydraulic power unit. Hydraulic fluid within the housing passes over the electric machine, thus cooling the electric machine and providing for improved efficiency and performance.
    Type: Application
    Filed: August 26, 2004
    Publication date: August 11, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventors: Michael Gandrud, Torben Frederiksen, Hans Esders
  • Current measuring circuit for a PWM driver and method of using the same
    Patent number: 6927561
    Abstract: A current measuring circuit for a PWM driver. The current measuring device measures the high side and low side currents of a PWM driver circuit before the currents reach the driver. A first measuring circuit measures the high side of the circuit and a second measuring circuit measures the low side of the circuit. The second measuring circuit also receives a signal from the first measuring circuit containing the current measurement measured by the first circuit and the second circuit then adds this current to the second circuit current and transmits a signal of the summed currents to a receiving device.
    Type: Grant
    Filed: January 2, 2004
    Date of Patent: August 9, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventor: Joseph J. Schottler
  • Method and means for monitoring torque in a hydraulic power unit
    Patent number: 6925892
    Abstract: The present invention is directed towards a hydraulic power unit including a housing, an internal hydraulic power means, an external hydraulic power means, and a mechanical power shaft associated with the hydraulic power means. In addition, the hydraulic power unit comprises a transducer adapted for measuring torque mounted in the housing in a non-contact relation to the mechanical power shaft adjacent a portion of the shaft imposed with a magnetic field. The hydraulic power unit further comprises a controller associated with the transducer to monitor the measured torque and adjust the operation of the hydraulic power unit accordingly.
    Type: Grant
    Filed: December 17, 2003
    Date of Patent: August 9, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventor: Michael D Gandrud
  • Closed circuit steering circuit for mobile vehicle
    Patent number: 6923290
    Abstract: A closed-circuit pump is provided that receives input from a steering unit in order to drive a steering cylinder. The closed-circuit pump is preferably a proportional bi-directional pump. The steering unit includes a steering wheel or similar device controlled by an operator. In one embodiment, the steering unit is a conventional hydraulic system that includes a servo pump. In another embodiment, the steering unit is an electronic displacement control system. The steering cylinder engages with a steering assembly to perform the steering function by physically turning the wheels of the vehicle. The inlet of the steering cylinder includes a counterbalance valve, which prevents flow into the steering cylinder when there is no steering input from the operator.
    Type: Grant
    Filed: May 27, 2004
    Date of Patent: August 2, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventors: Ian J. C. MacLeod, Rick J. Sporrer
  • Closed circuit steering circuit for mobile vehicles
    Patent number: 6923289
    Abstract: A closed-circuit pump is provided that receives input from a steering unit in order to drive a steering cylinder. The closed-circuit pump is preferably a proportional bi-directional pump. The steering unit includes a steering wheel or similar device controlled by an operator. In one embodiment, the steering unit is a conventional hydraulic system that includes a servo pump. In another embodiment, the steering unit is an electronic displacement control system. The steering cylinder engages with a steering assembly to perform the steering function by physically turning the wheels of the vehicle. The inlet of the steering cylinder includes a counterbalance valve, which prevents flow into the steering cylinder when there is no steering input from the operator.
    Type: Grant
    Filed: September 11, 2003
    Date of Patent: August 2, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventors: Ian J. C. MacLeod, Rick J. Sporrer
  • Vehicle steering system and method of steering
    Patent number: 6912455
    Abstract: A method for steering a vehicle, in which a steering motor (4) is activated in dependence of the activation of a steering member (1), a steering motor angle and a steering member angle are detected and an error in the correlation between the steering member (1) and the steering motor (4) is compensated, stored data being used for the compensation of the error. Further, the invention concerns a steering arrangement (100).
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: June 28, 2005
    Assignee: Sauer-Danfoss (Nordborg) A/S
    Inventor: Johan van Beek
  • Decoupled check-relief valve
    Patent number: 6910502
    Abstract: A decoupled check-relief valve for use in a hydraulic fluid circuit is provided that has a cylindrical guide housing which travels during the check function of the valve. The cylindrical guide housing has a clearance parameter, allowing for the selection of an optimal check response time. A dampening disk is provided inside the cylindrical guide housing, traveling within the guide during the relief function of the valve. The dampening disk has a separate clearance parameter, allowing for the selection of an optimal dampening capacity and fluid circuit stability. As such, the check and relief clearance parameters are independent of each other to allow both the check and relief functions of the valve to be optimized.
    Type: Grant
    Filed: April 1, 2003
    Date of Patent: June 28, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventor: Kevin J. Landhuis
  • METHOD AND MEANS FOR MONITORING TORQUE IN A HYDRAULIC POWER UNIT
    Publication number: 20050132817
    Abstract: The present invention is directed towards a hydraulic power unit including a housing, an internal hydraulic power means, an external hydraulic power means, and a mechanical power shaft associated with the hydraulic power means. In addition, the hydraulic power unit comprises a transducer adapted for measuring torque mounted in the housing in a non-contact relation to the mechanical power shaft adjacent a portion of the shaft imposed with a magnetic field. The hydraulic power unit further comprises a controller associated with the transducer to monitor the measured torque and adjust the operation of the hydraulic power unit accordingly.
    Type: Application
    Filed: December 17, 2003
    Publication date: June 23, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventor: Michael Gandrud
  • Compact vehicle transmission
    Patent number: 6904997
    Abstract: A compact vehicle has a frame and an operating position thereon for at least one rider. An engine having a drive shaft is on the frame, as are a plurality of operational wheels. A transmission operatively couples the engine and the wheels. The transmission is a hydrostatic mechanical transmission with at least 2 operational modes.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: June 14, 2005
    Assignee: Sauer-Danfoss, Inc.
    Inventor: Frederic W. Pollman
  • Arrangement for filtering hydraulic fluid
    Publication number: 20050121373
    Abstract: An arrangement for filtering a hydraulic fluid having a bypass line connecting the feed channel to the discharge channel where the bypass line is opened by a pressure switching valve when a pressure change is caused by the contamination of the filter element.
    Type: Application
    Filed: October 27, 2004
    Publication date: June 9, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventor: Reinhardt Thoms
  • Dual check-relief valve
    Publication number: 20050097887
    Abstract: A dual check and high pressure relief valve that is able to perform the function of a hydrostatic high pressure relief valve and a check valve. The new valve has two poppets separated by a spring that are within two seats within a guide and secured by a plug. By adjusting the seats the relief pressure setting is set. The dual check and high pressure relief valve has three separate passageways that allow fluid flow between different combinations of the passages depending upon the function desired within the hydrostatic circuit. A dashpot is also included between the two poppets to provide positive dampening of the system.
    Type: Application
    Filed: November 10, 2003
    Publication date: May 12, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventor: Kevin Landhuis
  • Control device for a hydraulic lifting arrangement
    Publication number: 20050092169
    Abstract: The invention concerns a control device for a hydraulic lifting arrangement with a drive in the form of a hydraulic motor, which has a first working connection and a second working connection, a pressure connection and a tank connection, and a control valve, which is connected with the pressure connection and the tank connection on the one side and with the first working connection via a first working pipe and with the second working connection via a second working pipe, each working pipe comprising a stop valve that can be opened.
    Type: Application
    Filed: October 21, 2004
    Publication date: May 5, 2005
    Applicant: Sauer-Danfoss ApS
    Inventor: Martin Joergensen
  • Transition valving by means of non-return valves
    Patent number: 6887054
    Abstract: A rotary fluid pressure device has a first oil passage with relatively high pressure fluid therein surrounding the gear set; a plurality of second oil passageways connecting the first oil passageway to the expanding and contracting oil chambers; and fluid non-return valves in each of the second oil passageways to permit the flow of oil therethrough only in a direction from the oil chambers to the first oil passageway.
    Type: Grant
    Filed: March 16, 2004
    Date of Patent: May 3, 2005
    Assignee: Sauer-Danfoss ApS
    Inventors: Hans Christian Petersen, Jorgen Pedersen
  • Transition valving by means of non-return valves
    Patent number: 6884048
    Abstract: A rotary fluid pressure device has a first oil passage with relatively high pressure fluid therein surrounding the gear set; a plurality of second oil passageways connecting the first oil passageway to the expanding and contracting oil chambers; and fluid non-return valves in each of the second oil passageways to permit the flow of oil therethrough only in a direction to the oil chambers from the first oil passageway to the oil chambers.
    Type: Grant
    Filed: September 26, 2002
    Date of Patent: April 26, 2005
    Assignee: Sauer-Danfoss (Nordborg)
    Inventors: Hans Christian Petersen, Jorgen Pedersen
  • Hydromechanical transmission electronic control system for high speed vehicles
    Publication number: 20050085979
    Abstract: An electronic transmission control system is provided that can achieve a transmission ratio based on the operator inputs and the current vehicle operating conditions. The transmission constantly connects the engine to the load, and the transmission ratio is only varied by a change in command from the present invention. The transmission's mechanical function is solely to vary the ratio between its input and output. In using the present invention, an operator must select an operating mode, either automatic or manual, using a two-position switch. While in the automatic mode, the present invention determines the vehicle speed by considering the position of the throttle and the operator's use of brakes. In the manual mode, the present invention further considers the operator's selection of a gear condition.
    Type: Application
    Filed: November 4, 2004
    Publication date: April 21, 2005
    Applicant: Sauer-Danfoss Inc.
    Inventors: Ryan Carlson, Manfred Maiers, Steven Gluck